Automatic hemming apparatus

ABSTRACT

This disclosure relates to an automatic hemmer which includes a conventional overedge sewing machine having special support and hem folding apparatus associated therewith. The hem folding apparatus includes means for assuring the elimination of a curl in advance of the hem folder, means for controlling movement of the material in advance of the hem folder, an ejector, and hem detecting means whereby the various components of the hem folding attachment and the operation of the sewing machine may be automatically controlled. The support apparatus may include means for supporting tubular material, such as an undershirt, whereby a continuous hem along one edge of the tubular material may be automatically sewn.

United States Patent 1191 Kosrow et a1.

1451 Jan. 22, 1974 [54] AUTOMATIC HEMMING APPARATUS FOREIGN PATENTS OR APPLICATIONS 1 Inventors: f Kmmw, Eioffman Estates; 37,611 10/1965 Germany 112/121.15 Alolzy Mrowczynskl, Des Flames. 1,072,871 1/1960 Germany 112/121.27 both of 111.

[73] Assignee: Union Special Machine Company, Primary Franklin Chicago, 11]. Assistant ExaminerPeter Nerbun Attorney, Agent, or Firm-Charles E. Brown et a]. [22] Filed: Oct. 20, 1971 [21] Appl. No.: 190,757 [57] ABSTRACT This disclosure relates to an automatic hemmer which [52] 11.8. CI. 112/143 includes a conventional overedge sewing machine hav- [51] Int. Cl D05b 35/04 ing special support and hem folding apparatus asso- [58] Field of Search 112/ 140-143, 136, ciated therewith. The hem folding apparatus includes 112/147, 152, 153, 63, 121.27, 121.26, 2, means for assuring the elimination ofa curl in advance 121.12, 121.15, 121.29, 177 of the hem folder, means for controlling movement of the material in advance of the hem folder, an ejector, [56] References Cited and hem detecting means whereby the various compo- UNITED STATES PATENTS nents of the hem folding attachment and the operation I7 224 5/1857 Marston 2/141 of the sewing machine may be automatically conl,282:026 10/1918 2/141 trolled. The support apparatus may include means for 3,134,347 5/1964 Seaman 112/147 Supporting tubular material, such as an undershirt, R20,161 11/1936 Riviere 112/121.27 whereby a continuous hem along one edge of the tu- 3,192,885 7/1965 Timm 112/140 bular material may be automatically sewn. 3,200,779 8/1965 Boser.... 112/152 3,515,081 6/1970 Miller 112/152 24 Chums, 22 Drflwmg Flgures Pmmmmz m4 3.786.768

' sum 1 am lNVENTDRs ROBERT L. KOSRDW 6r ALEHZY MRDLUCZYNSN PATENTEnmzz mm 3.786; 768

IEIGJS mvemmzs mar-m LMDSRDLU & mmzY MRDUUCZYNSK! ATTO ENEYS PAIENTEDJM 22 1974 SHEET 8 0F 8 du oumua @QK M Em m wS m m 43mm,

INVE NTORS ROBERT L.KUSIZDLU ALDIZY MRDLUCZXNSN ATT RNEYS AUTOMATIC HEMMING APPARATUS This invention relates in general to new and useful improvements in sewing machines, and more particularly to a sewing machine having incorporated therewith an automatic hem folding attachment.

' BACKGROUND OF. THE INVENTION It is well known to provide hem folding attachments for sewing machines. It is also well known to provide sewing machines which will automatically hem material and automatically discontinue the hemming operation at the remote edges of material. However, more than this is required for a commercially acceptable hem folding apparatus at this time.

SUMMARY OF THE INVENTION There has been recently developed a hem folding attachment which includes first and second folder sections each mounted for movement between an operative position and a closed position whereby material to be hemmed may be readily positioned within the folder attachment and removed therefrom. In accordance with this invention it has been found that the relative movement and positioning of these first and second folder sections by automatically controlled mechanism is commercially practical.

Further in accordance with this invention, there has been developed suitable material guidance apparatus which will facilitate the automatic guiding of material to be hemmed in advance of the hem folding attachment, and this guidance apparatus is alsoautomatically movable between operative and inoperative positions.

One of the features of the guidance apparatus is that it will assure the presentation to the hem folding attachment of a material edge which is uncurled and prepared for instant folding within the hem folding attachment. In a preferred embodiment of the invention the guidance attachment may be in the form of a prefolder which will provide for an initial folding of the material, thereby greatly facilitating the final hem folding operation by the hem folding attachment.

Still another feature of this invention is the provision of a material ejector in advance of the hem folding attachment whereby when it is determined that a hemming operation is to terminate, the material may be moved relative to the hem folding attachment and the associated sewing machine and the hemming operation automatically discontinued. In association with the ejector, a detector may be provided to effect the automatic detection of the point of termination of the hemming operation and controls actuated by the detector maybe utilized to actuate the ejector and move the folder sections to an open position to permit the discharge of the hemmed material.

A principal feature of this invention is the provision of an automatic control system wherein a machine operator need only to properly position material to be hemmed relative to the automatic hemming apparatus and then actuate the control circuit with the result that the material will be automatically guided, folded and sewn in the necessary order to produce the required hem, and at the desired point of termination, the automatic hemming apparatus will suitably release the material and move the same relative to the sewing-machine so as to assure the completion of the sewing operation and the discharge of the material from the sewing machine, as well as the automatic discontinuing of the operation of the sewing machine.

The automatic hemming apparatus is particularly adapted for hemming an edge of tubular material, such as undershirts. To this end, the automatic hemming apparatus also includes suitable support apparatus for the material to be hemmed. This support apparatus includes at least one work support cylinder or roller associated with the conventional cloth plate of the sewing machine for supporting the material. In addition, there may be associated with the support cylinder a material tensioning roller which will serve to stretch or tension the material being hemmed both over the cloth plate of the sewing machine and the support cylinder or cylinders associated therewith. This will assure the proper supporting of the tubular material while one edge thereof is being hemmed.

Still another feature of the invention is the provision of an automatic control circuit which includes a timer whereby material having a seam or seams incorporated therein may be automatically hemmed without the detection of the seam or seams improperly automatically effecting the termination of the hemming operation, the timing device serving to render the detector inoperative until the seam or seams have passed.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings:

In the drawings:

FIG. 1 is a front elevational view of a sewing machine incorporating the hem folder.

FIG. 2 is an enlarged fragmentary plan view of a portion of the sewing machine of FIG. 1 and shows specifically the details of the hem folder and the relationship thereof to other components of the sewing machine.

FIG. 3 is a rotated elevational view of the hem folder removed from the sewing machine.

FIG. 4 is a fragmentary end elevational view of the hem folder taken from the right in FIG. 3 with a portion of a folder section broken away.

FIG. 5 is a vertical sectional view taken along the line 55 of FIG. 3.

FIG. 6 is a schematic elevational view showing the manner in which the folder sections may be positioned by means of hydraulic cylinders.

FIG. 7 is a schematic elevational view showing the relationship of the hem folding attachment with respect to a cloth plate and a needle of a sewing machine and shows the specific position of material therein folded ready for stitching.

FIG. 8 is a plan view of a sewing machine having associated therewith an automatic hemming apparatus incorporating the hem folding attachment of FIGS. 1 through 7.

FIG. 9 is an end elevational view of the sewing machine and hem folding attachment of FIG. 8.

FIG. 10 is a front elevational view of the sewing machine of FIG. 8 with parts thereof broken away and shows the specific details of the means for effecting the automatic operation of the hem folding attachment.

FIG. 11 is an elevational view showing the details of a control switch for the automatic hemming apparatus.

. FIG. 12 is a fragmentary sectional view showing the specific details of the mounting of a detecting lever for the control switch.

FIG. 13 is a front elevational view of the sewing machine and automatic hem folding apparatus of FIG. 8 having associated therewith support apparatus for the supporting of tubular material during an automatic hemming of one edge thereof.

FIG. 14 is a fragmentary horizontal sectional view taken along the line 14-14 of FIG. 13 and shows the specific details of an uncurler associated with the support apparatus.

FIG. 15 is a plan view of the automatic hemming apparatus of FIG. 13 and shows further details thereof.

FIG. 16 is an end elevational view of the automatic hemming apparatus of FIG. 13 and shows still further details thereof.

FIG. 17 is a combined electrical and fluid schematic of the control system for the automatic hemming apparatus.

FIG. 18 is an elevational view on an enlarged scale of a modified form of edge guidance attachment which incorporate a prefolder.

FIG. 19 is sierra aisvaiisaarview of thed eguid ance apparatus of FIG. 18 taken from the left end thereof.

FIG. 20 is a fragmentary front elevationalview 0H5? FIG. 22 is a fragmentary schematic showing the details of a modification to the control system of FIG. 17 as required by the edge guidance apparatus of FIG. 18.

Referring now to the drawings in detail, it will be seen that there is illustrated in FIG. 1 a conventional sewing machine which is generally identified by the numeral 20 and for descriptive purposes, may be considered to be of the type disclosed in the US. Pat. to Wallenberg, et al., No. 2,704,042, granted Mar. 15, 1955. The sewing machine 20 includes a frame 21 which has mounted thereon in the customary manner a cloth plate 22, a needle arm 23, which supports a needle 24, and a presser foot (FIG. 2).

In accordance with this invention there is mounted on the frame 21 in association with the cloth plate 22 a material folder assembly, generally identified by the numeral 26, the material folder assembly 26 being positioned for folding material in advance of movement thereof beneath the presser foot 25 for the sewing thereof by the needle 24. The specifically illustrated material folder assembly is a hem folder, and the sewing machine 20 is an overedge sewing machine equipped to produce a blindstitch seam. This is the preferred embodiment or use of the invention, but it is to be understood that the principals of the folder construction are not restricted to one utilized in a blindstitch hemming operation, and the configuration of the material folding sections, to be described hereinafter may be varied in accordance with the particular requirements of a desired material folding operation.

Referring now to FIG. 3 in particular, it will be seen that the folder assembly 26 includes a support bracket 27 which is provided on one face thereof with a vertically extending key type projection 28. The projection 28 is tightly receivable within a groove (not shown) in a knife support block 30 (FIG. 1) of the sewing machine 20. A screw 31 carried by the support bracket 27 extends through the projection 28 and is threadable into a threaded bore (not shown) in the knife support block 30 to rigidly, yet removably, mount the support bracket 27.

It is to be noted that the support bracket 27 is of a Z- shaped configuration, in elevation, and that portion thereof remote from the projection 28 has formed in the upper surface thereof a groove 32 in which there is slidably received a key-type projection 33 of a block 34. The block 34, which is slidably mounted on the support bracket 27, is claimed in an adjusted position thereof to the support bracket 27 by means of a screw 35. The screw 35 freely passes through an elongated slot 36 in the support bracket 27 and is threaded into the underside of the block 34.

In order that the block 34 may be readily adjusted relative to the support bracket 27, the extreme end of the support bracket 27 remote from the projection 28 has threaded thereinto a knurled head shoulder screw 37. An arm 38 is carried by the screw 37 for movement therewith while permitting relative rotation of the screw 37. The arm 38 extends substantially vertically and has the upper end thereof fixedly secured to the end of the block 34 by means of a screw 40. Thus, by rotating the screw 37, the block 34 may be accurately positioned relative to the support bracket 27.

The upper part of the end of the block 34 remote from the arm 38 is notched and has seated therein an edge guide member 41. The edge guide member 41 is secured in place by means of a screw 42.

A stepped bracket 43 is removably secured in overlying supported relation to the block 34 by means of a screw 44. An elevated upper portion of the bracket 43 has an oblique upper surface which is provided with a groove45 in which there is received in sliding relation, a strip member 46. The strip member 46 is slidably retained within the groove 45 by means of a cover plate 47 which is secured to the bracket 43 by means of suitable fasteners 48.

The strip 46 has a downwardly sloping inner end portion 50 which is provided with a pair of upturned side walls 51. Between these side walls there is received a mounting portion of a first, movable, folder section 52. A screw 53 serves to rigidly secure the mounting portion of the folder section 52 to the strip member 46.

The guide bracket 43 (FIG. 5) has formed in the underside thereof a groove 54 which is closed by the upper surface of the block 34 and which has received therein for sliding movement, a tongue shaped second folder section 55.

It is to be noted that the folder section 52 is generally U-shaped in elevation and includes a lower blade 56 having an elongated outline, as is best shown in FIG. 2. An edge or tip 57 of the blade 56 terminates adjacent the edge guide 41 and cooperates therewith in the folding of material.

It is to be noted that the upper part of the folder section 52 is provided along the forward edge thereof with a depending flange 58. It will be readily apparent from the schematic showing of FIG. 7 that the flange 58 cooperates with the remainder of the first folder section to maintain the alignment of material within the folder.

The second folder section has the free end thereof projecting into the folder section 52 and terminates in a tapered tongue 60 having a widened outline, as is best shown in FIG. 2. It is to be understood that material being folded within the folder section 52 will be folded around the tongue 60.

In order to facilitate the insertion and removal of material from the folder assembly 26, the folder sections 52 and 55 are movable in generally opposite directions. In order to facilitate this movement, a link 61 is connected to a terminal portion 62 of the strap member 46 in any desired manner. A somewhat similar link 63 is secured to that end of the second folder section 55 remote from the tongue 60 thereof. It is to be understood that the links 61 and 63 may be reciprocated in any practical manner in order to effect the opening and closing of the folder assembly 26. Alternative operating mechanisms are illustrated in FIGS. 1 and 6.

With reference to FIG. 1, it will be seen that a suitable upright plate 64 is mounted at the front of the frame of the sewing machine 20. The plate 64 has pivotally mounted thereon a T-shaped lever 65, the lever 65 being carried by a pivot member 66 which may be in the form of a shoulder screw. The T-shaped lever includes an upright bar portion which includes an upper leg 67 and a lower leg 68, and a generally horizontally disposed stem portion 70.

A spring7l extends between the leg 67 and the plate 64 and constantly urges the lever 65 in a counterclockwise direction. Pivoting of the lever 65 in a counterclockwise direction is limited by means of a stop pin 72, which is engaged by the leg 68.

It is to be noted that a'guide sleeve 73 is suitably mounted on the plate 64 and has slidably received therein an intermediate portion of the link 61, the link 61 being in the form of a wire. The end of the wire 61 remote from the strap member 46 is connected to the leg 68 by means of an adjustable clamp 74 rotatably carried by the leg 68. In a like manner, the link 63 is in the form of a wire which is adjustably secured to the leg 67 by means of a clamp member 75 which is rotatably carried by the leg 67. The wire 63 extends through a guide tube 76 carried by the upper part of the plate 64.

The sewing machine has associated therewith a treadle 77 whichis illustrated as being a foot actuated treadle, but which could be, any actuated treadle. The treadle has connected thereto a wire or link 78 which has the opposite end thereof connected to the stem 70. It will be readily apparent that when the treadle 77 is depressed, the lever 65 will be rotated in a clockwise direction and the wire 61 will push the first folder section 52 to the left, as viewed in FIG. 1. At the same time, the wire 63 will pull the second folder section 55 to the right. In this manner, the folder sections 52 and 55 are simultaneously moved apart in a transverse direction. Further, inasmuch as the folder section 52 is carried by the strap member 46 and movement of the strap member 46 generally to the left in FIG. 1 will also result in movement of the strap member upwardly, it will be seen that when the folder section 52 is moved to the left to an open position, it is also moved laterally upwardly away from the cloth plate 22 so as to provide a greater spacing between the folder section 52 and the cloth plate 22 with the result that cloth may be more easily fed into or removed from the folder assembly 26.

Reference is now made to the schematic illustration of FIG. 6 wherein it will be seen that the links 61 and 63 have been illustrated as piston rods of extensible first folder section 52 in conjunction with the edgefluid cylinders 80 and 81, respectively. The fluid cylinders 80 and 81 may be mounted on the sewing machine 20 in any desired manner and will be parts of a conventional fluid system which may be controlled by any desired type of valve (not shown). It is to be understood that the extensible fluid motors 80,81 are preferably of the single acting type although they could be of the double acting type. The extensible fluid cylinders 80,81 will be connected in the conventional fluid system so as to operate in unison.

OPERATION With particular reference to FIG. 7, it will be seen that the material M which is to be hemmed is principally supported by the cloth plate 22 and has the marginal portion thereof feeding through the folder assembly 26. The marginal portion of the material is first reversely folded about the tip 57 of the blade 56 of the guide 41. The marginal portion of the material is then reversely folded about the tongue 60 of the second folder section 55 and extends in the space between the upper surface'of the second folder section 55 and the upper part of the first folder section 52.

It is to be noted that the first reverse fold of the material M, that is the fold about the plate 57 is generally aligned with the needle 24. On the other hand, the extreme marginal edge of the material extends to the right, as viewed in FIG. 7, beyond this fold. The sewing machine 20 may be equipped wiht a knife (not shown) which will trim the extra material before the necessary stitching has been effected.

Reference is now made to FIGS. 8 through 12 wherein the sewing machine 20 and the folder assembly 26 are illustrated as parts of an automatic hemming apparatus, which apparatus is generally identified by the numeral 90. In this apparatus, the sewing machine 20 and the folder assembly 26 remain unchanged. However, as is generally shown in FIG. 6, the folder sections 52 and 55 may be automatically positioned by remote controls. To this end, with particular reference to FIG. 10, it will be seen that the sewing machine 20 is provided with a mounting plate 91 which generally corresponds to the mounting plate 64 and which has mounted thereon means for the automatic positioning of the folder sections 52 and 55. The position of the folder section 55 is controlled by means of an air cylinder 92 which is mounted on the plate 91 by means of a bracket 93 and which has a piston rod 94. The piston rod 94 has adjustably mounted thereon by means of a pair of nuts 95 an elongated clamp member 96 which, in turn, has adjustably secured thereto one end portion of a wire 97, the other end portion of the wire 97 being connected to the folder section 55. An intermediate portion of the wire 97 is carried by a sleeve 98 which, in turn, is supported by the plate 91.

An air cylinder 100 is also mounted on the plate 91 by means of a bracket 101. The air cylinder 100 includes a piston rod 102 which has adjustably mounted thereon by means of nuts 103 an elongated clamp member 104. One end of a wire 105 is adjustably secured to the clamp member with the wire 105 passing through a tubular guide 106 carried by the plate 91. The opposite end of the wire 105 is adjustably secured to the folder section 52 by means of a fitting 107.

The automatic hemming apparatus 91) also includes an edge guidance apparatus which is generally identified by the numeral 108 and which is best illustrated in FIGS. 8 and 9. The apparatus 108 includes a conventional table 110 on which the sewing machine is mounted. Along the front edge of the table 110 there is mounted a generally Z-shaped bracket 111 which, in turn, serves as a support for a mounting plate 112. The bracket 111 is secured to the table 110 by means of fasteners 113 while the mounting plate 112 is secured to the bracket 111 by means of suitable fasteners 114.

The plate 112 has mounted on the lower portion thereof a base plate 117 which is formed at one of its ends with a pair of upturned ears 118 to which is pivotally connected an air cylinder 120 by means of a pin 121. This air cylinder 120 is preferably of the single acting type having a piston rod 122 which has secured on the free end thereof a clevis 123 which is, in turn, secured to an arm 124 rigidly carried by a clamp 125 which cooperates with the plate 112 in the guidance of material to be hemmed. It is to be noted that the clamp 125 basically includes an elongated leg 126 which has a free end thereof pivotally mounted by means of a pin 127 carried by ears 128 formed on the base plate 117 remote from the ears 118. The clamp 125 is provided at the opposite end thereof with an offset U-shaped portion 130 which terminates in a clamping foot 131 which directly opposes the plate 112 and which has a curved free edge 132 generally aligned with the edge 57 of the blade 56. It is to be understood that in the normal position of the cylinder 120, the clamp 125 will be spaced from the plate 112 and when the cylinder 120 is activated, the clamp 125 will cooperate with the plate 112 in the guidance and prefolding of material to be hemmed.

The plate 112 has mounted thereon above and to the right of the edge 132 of the clamp 125 an edge guide generally identified by the numeral 133. The edge guide 133 includes a plate 134 which is adjustably secured to the plate 112 by means of a screw 135. The plate 134, in turn, has mounted thereon a substantially triangularly shaped plate 136 which is mounted by its small, right-hand end, onto the plate 134. The wider portion of the plate 136 extends beyond the plate 134 and together with the plate 134, forms a device for prefolding the edge portion of the material to be hemmed.

Mounted on the plate 112 between the clamp 125 and the edge guide or prefolder 133 is a control switch assembly generally identified by the numeral 137. With particular reference to FIGS. 11 and 12, it will be seen that the switch assembly 137 includes a switch 138 which is mounted on the under or rear side of the plate 112 (FIG. 9) and which has an arcuate actuator 140. Operation of the switch 138 is controlled by a lever assembly, generally identified by the numeral 141, pivotally mounted on the plate 112.

The lever assembly 141 includes a shouldered bushing 142 which is fixed within the plate 112 and which has rotatably mounted therein an inner bushing 143 which is internally threaded. A lever 144 is secured to one end of the bushing 143 by a fastener 145 threaded therein, while the lever 146 is secured to the opposite end of the bushing 143 by a second fastener 147 threaded therein. In this manner the levers 144,146 are adjustably interconnected for rotation in unison.

It is to be noted that the lever 146 has an arcuate extension 148 which is reversely curved as compared to the arcuate actuator 140 and is engaged therewith for moving the switch 138, which is a normally closed switch, to an open position upon the rotation of the levers 144, 146, in a clockwise direction.

It is to be noted that the lever 144 includes an elongated material engaging finger 150 and an offset stop flange 151 at the opposite ends thereof. The material engaging finger is intended to overlie material passing under the clamp and is offset from the plate 112 sufficiently to normally permit the passage of material therebeneath without actuation of the lever 144. The lever 144 is adjustable relative to the plate 112 through the provision ofa slot 152 through which the screw passes. Also, rotation of the lever 144 in a counterclockwise direction is prevented by engagement of the stop flange 151 with the lower edge of the plate 134. It is to be understood that the lever 144 will normally be stationary and is moved only when it is engaged by a bulging portion of the work, such as a prior formed hem portion.

For pushing the workpiece out of the folder assembly 26, which will become necessary after the hemming operation has been completed, in order to close the seam, there is provided an ejection device, which is generally identified by the numeral 154. The ejection device includes a rearwardly bent upper portion 155 of the plate 112. This upper portion 155 is provided with a longitudinally elongated slot 156. Aligned with the slot 156 is a horizontally disposed air cylinder 157 which is supported from the rear surface of the plate 112 by means of a bracket 158.

The cylinder 157 includes a piston rod 160 which has mounted on the free end thereof a fitting 161 which, in turn, carries a rod or finger 162 which extends through the slot 156 and terminates forwardly and upwardly of the plate portion 155 in a hooked end. It is to be noted that the finger or rod 162 is normally disposed to the right of the path of the edge material being hemmed and is thus in an out-of-the-way position. However, the stroke of the air cylinder 157 is sufficient to permit the finger 162 to be moved further enough to the left to engage the edges of the material being hemmed and to move the material to the left out of the folder assembly 26 and guide the same away from the needle 24 of the sewing machine.

No attempt has been made in FIGS. 8 through 12 to illustrate the specific details of the control mechanism of the sewing machine 20 and the manner in which it is supported. However, reference is now made to FIGS. 13 and 16 in particular wherein it will be seen that the supporting structure 110 is carried by an upright column 165 which may be provided with a floor engaging base (not shown). The upper part of the supporting structure 110 may be in the form of a conventional table 166. An electric transmitter 167 is secured to the undersurface of the table top 166 and comprises an electric motor and a clutch unit, both of which are conventional. It is to be noted that the transmitter 167 is positioned towards the right of the sewing machine, as viewed in FIG. 13, and to the rear of the sewing machine, as viewed in FIG. 16. The electric transmitter 167 is provided with a drive pulley 168 which is operatively connected to the sewing machine 20 by means of a drive belt 170.

For operating the transmitter 167, there is provided a clutch lever 171. The clutch lever 171 is actuated by means of an air cylinder 172 mounted thereon. The air cylinder 172 has a piston rod 173 which engages against the transmitter housing and upon actuation of the cylinder 172 will cause the clutch lever 171 to be pushed away from the transmitter housing.

Also, as is best shown in FIGS. 13 and 16, a box-like housing 175 is suitably secured to the table 166. The housing 175 contains electrical and pneumatic control equipment for the automatic mechanism of the automatic hemming apparatus. The details of this control equipment will be generally disclosed hereinafter.

There is also shown in conjunction with the sewing machine 20, a presser foot lifting air cylinder 176 which is carried by a support bracket 177 mounted on the top cover of the sewing machine 20. The cylinder 176 is of a conventional construction and is conventionally connected to the presser foot lifter mechanism of the sewing machine 20 operating the same.

While it is to be understood that the aforedescribed sewing machine and automatic hemming apparatus may be advantageously utilized with all types of materials, in view of the fact that a primary usage of the automatic hemming apparatus is in conjunction with tubular workpieces, such as T-shirts and the like, there is associated with the sewing machine 20 and the automatic hemming apparatus 90 a workpiece supporting system generally identified by the numeral 178. The workpiece supporting system 178 includes a pair of horizontally disposed, cylindrical members 180,181 resembling squirrel cages or the like. Each of these cylindrical members 180,181 is supported for free rotary movement on an individual shaft 182 and constrained against axial movement on the shaft by means of collars 183. Each shaft 182 is secured to an individual bracket arm 184 in any desired manner, but particularly by means of welding. Each bracket arm 184 is adjustably secured to an end of the table top 166 by means of a bolt 185 which is preferably seated in an elongated slot in the bracket arm 184 so as to facilitate adjustment thereof. It is to be noted that the upper surfaces of the cylindrical members 180,181 lie generally coplanar with the cloth plate 22. It is also to be noted that a portion of the surface of the cylindrical member 180 corre sponds generally to the outline of adjacent portions of the plate 112 and the bent portion 155 thereof.

With particular reference to FIG. 13, it will be seen that the support column 165 has adjustably mounted thereon a pair of mounting rings 186. The mounting rings are vertically spaced on the support column 165 and each mounting ring 186 is provided with a bracket 187 extending substantially horizontally therefrom. The brackets 187 carry a vertically disposed guide plate 188. As is clearly shown in FIG. 14, the guide plate 188 is provided along each side with a step 190 which steps 190 are engaged in sliding relation by guide blocks 191 carried by a plate 192. The plate 192 is maintained in a vertically adjusted position on the guide plate 188 by means of a thumb screw 193 carried by one of the guide blocks 191.

Medianly of the steps 190, the plate 188 is provided with a vertical groove 194 of a substantially square cross sectional shape. The groove 194 serves as a guide' for a shaft 195 which extends horizontally from the plate 188 with one of its ends being seated in the groove 194. The shaft 195 is arranged for vertical movement along the groove 194 whereby the end which extends into the groove 194 carries an antifriction bearing 196.

The shaft 195 is rigidly secured in a bore provided in a block 197 which is mounted on the free end of a piston rod 198 of a vertically disposed air cylinder 200 (FIG. 16). The air cylinder 200 is mounted on the bracket plate 192 in generally depending relation by means of an angle bracket 201 and is of the double acting type having ports 202 and 203 at the upper and lower ends, respectively, thereof.

Due to the particular mounting of the shaft in the block 197, there is a small shaft portion and a large shaft portion extending from the block 197. The small shaft portion carries the aforementioned bearing 196 while the large shaft portion carries a freely rotating roller 204 which is constrained against endwise move ment of the shaft 195 by means of a pair of collars 205.

As is best shown in FIG. 16, there is secured to the plate 192 an air switch 206 in such a fashion that a switch button 207 thereof is engaged by a contact arm 208 carried by the piston rod 198 when the piston rod 198 is retracted.

Secured to the plate 192 is an angle bracket 210 which serves as a support for an uncurler arrangement generally identified by the numeral 211. The uncurler arrangement 211 includes an air cylinder 212 which is secured to the bracket 210 by means of a bracket 213. The air cylinder 212 has a piston rod 214 which is provided with a clevis 215 by which the piston rod 214 is pivotally connected with a lever 216 of the 3rd order. The lever 216 is pivotally mounted on the bracket 210 by means of a pivot stud 217 and has secured at its other end an uncurler plate 218. The air cylinder 212 is of the single action type and normally serves to hold the uncurler plate 218 in a retracted position.

With particular reference to FIGS. 13 and 16, it will be seen that the uncurler plate 218 is disposed vertically above the roller 204 in a position to engage tubular material as it passes downwardly from the cylindrical member 181 and around the roller 204 to uncurl the edge of tubular material before it passes around the roller 204 and possibly become creased by its engagement with the roller 204.

At this time it is pointed out that the operative position of the roller 204 is adjustable in accordance with the size of the tubular material being hemmed. This is accomplished by adjusting the position of the plate 192 on the guide plate 188 thus vertically adjusting the air cylinder 200 and the roller 204 carried thereby.

Referring now to FIG. 17 with particular reference to the fluid system schematically illustrated therein, it will be seen that there is illustrated a line 220 which is connected to a source of compressed air (not shown). Incorporated in the air line 220 are conventional filter 221 and air line lubricators 222. Between the air line lubricator and filter there is a pressure regulator valve 223. A branch line 224 extends from the line 220 intermediate the pressure regulator 223 and the air line lubricator 222. Incorporated in the air line 224 is a normally open solenoid actuated valve 225. The line 224 leads through a pressure regulating valve 226 to an air jet 227 for the chain cutter (not shown) which is a conventional part of the sewing machine 20. A branch line 228 leads from the line 224 to the cylinder 157 and has incorporated therein an adjustable flow control valve 230.

Another branch line 231 extends from the line 220 beyond the air line lubricator 222 and leads to a normally closed solenoid control valve 232 which controls the operation of the cylinder 176 for the presser foot lifter. Incorporated in the line 231 between the cylinder 176 and the valve 232 is a one-way flow control valve 233.

Branching off of the line 231 is a line 234 which leads to the cylinder 172 for the transmitter clutch. Flow through the line 234 is controlled by means of a normally open solenoid controlled valve 235 and by means of a flow control valve 236. I

The line 220 leads to the air cylinder 212 for the uncurler. Incorporated in the line 220 in advance of the cylinder 212 is a flow control valve 237 and the air valve 206.

Leading from the line 220 is a branch line 238 which leads to the air cylinder 92 for the folder section 55. Flow into the line 238 is controlled by a normally open solenoid controlled valve 240 and by a normally open solenoid controlled valve 241. A flow control valve 242 is also incorporated in the line 238.

A branch line 243 leads from the line 238 from between the valves 240,241 and leads to the cylinder 120 for the clamp. Flow through the line 243 is controlled by a normally open solenoid controlled valve 244 and a flow control valve 245 is incorporated in the line 243 in advance of the cylinder 120.

A branch line 246 leads from the line 243 in advance of the flow control valve 245 and is connected to the cylinder 100 for the folder section 52. A flow control valve 247 is incorporated in the line 246.

A further line 248 branches off of the line 243 in advance of the line 246 and is connected to the lower end of the double acting cylinder 200. An adjustable flow control valve 250 is incorporated in the line 248 in series with a one way quick exhaust valve 251.

A line 252 leads from the line 220 in advance of the flow control valve 236 to the upper end of the double acting cylinder 200. An air regulator 253 is incorporated in the line 252.

It will be apparent that the pressure at the port 203 is higher than the pressure at the port 202 due to the setting of the regulator 253. Thus, the pressure at the port 203 overrides the pressure at the port 202 as long as the apparatus is in its at rest or inoperative condition.

Reference is now made to the electrical system of FIG. 17. It is to be noted that the system is of the type utilizing the conventional grounded terminal and hot terminal. The grounded terminals and the hot terminals w be l d wit 2 Source o 1 ts 99329 alternating current, although other power supplies may be utilized. The electrical system includes a hot terminal 255 to which a line 256 having a manually operable, normally open, switch 257 therein is connected. The line 256 goes to an actuating coil 258 of a two-position switch 260. A further line 261 extends from the coil 258 to ground with the normally closed switch 138 being incorporatd in the line 261.

The switch 260 includes a pair of fixed contacts 262 and 263 and a movable contact 264, the movable contact 264 normally engaging the contact 262 and being movable into engagement with the contact 263 when the coil 258 is energized. A line 265 leads from the contact 263 to the solenoid control valve 241. A lead 266 extends between the wire or line 256 to the line or wire 265.

The electrical system includes a timer 267 which includes a grounded lead 268, a line 270 connected to the line 265, a line 271 connected to the line 261 on the grounded side of the switch 138, and a lead 272 connected to the line 261 on the coil side of the switch 138. It is to be understood that the timer 267 is a conventional timer and when energized by the closing of the switch 257 will maintain a circuit between the hot terminal 255 and the grounded contact 268 for a predetermined period of time. This circuit will parallel the circuit contained in the switch 138 and will cause the coil 258 to be energized even if the switch 138 should open.

At this time it is pointed out that although the switch 138 is a mechanically actuated switch whose opening is controlled by the engagement of the finger with a seam or like protrusion on a workpiece, the switch 138 may be controlled by other types of detectors, including a photoelectric cell or an air detector.

The electrical circuitry includes another multiple contact switch, generally identified by the numeral 273 which includes a first set of fixed contacts 274 and 275 having associated there with a movable contact 276. The switch 273 also includes a second set of fixed contacts 277 and 278 having associated therewith a movable contact 280. The contacts 276 and 280 normally engage the contacts 274 and 277, respectively. However, the contacts 276 and 280 are simultaneously movable into engagement with the contacts 275 and 278, respectively, through the energization of a control coil or solenoid 281. One end of the coil 281 is grounded and a lead 282 from the opposite end of the coil leads to a contact of a second timer, generally identified by the numeral 283. the timer 283 is of a conventional construction and includes a grounded contact 284. The timer 283 is connected to the contact 262 of the switch 260 by a lead 285 and to the line 256 in direct coupling with the terminal 255 by a wire 286. A further wire 287 extends from the wire 286 to the movable contact 264.

The energization of the coil 258 and the actuation of the switch 260 will effect a resetting of the timer 283. This, in turn, will result in the energization of the coil 281 to shift the movable contacts 276 and 280 of the switch 273.

The electrical circuitry includes a further switch 288 which includes a set of fixed contacts 290 and 291 having associated therewith a movable contact 292 which normally engages the contact 290. Switch 288 also includes a set of fixed contacts 293 and 294 selectively engageable by movable contact 295 which normally engages the contact 293. Positioning the contacts 292 and 295 is controlled by a coil 296.

One lead 297 of the coil 296 is connected to ground while a second lead 298 of the coil 296 is connected to a potentiometer 300. A capacitor 301 is shunted across the coil 296 between the leads 297,298. The potentiometer is connected to the contact278 by a lead 302 which has incorporated therein a diode 303.

Referring once again to the switch 288, it will be seen that the contact 295 is connected to the contact 274 of switch 273 by a lead 304. The fixed contact 294 is connected by a lead 305 to the solenoid controlled valve 225. A lead 306 connects the solenoid controlled valves 232 and 235 to the contact 291. The contact 290 has no function in the illustrated control system, and the contact 292 is connected by a lead 207 to a hot terminal 308. It is also pointed out at this time that a lead 309 connects the solenoid control valve 244 to the fixed contact 275 of the switch 273.

The solenoid controlled valve 240 is directly connected to a further hot terminal 310 by a lead 311 having incorporated therein a normally open, operator closeable switch 312.

' OPERATION A typical workpiece for which the apparatus of this invention is designed is a tubular workpiece having no seam or one or more seams. The invention will be described in conjunction with a workpiece having one seam.

In the operative condition of the apparatus, the valve 232 is closed and the cylinder 176 is under pressure, causing the presser foot 25 to be raised. The needle 24 is up, and the folder assembly 26 is open due to the movement apart of the folder sections 52,55 by the cylinders 92,100 which are pressurized in view of the fact that the valves 241,244 controlling the sameare normally closed. In a like manner, the clamp 125 is open in that the cylinder 120 is pressurized, the cylinder 120 being controlled by the valve 244. On the other hand,

the chain cutter jet 227 is inoperative as is the ejector portion into the open folder assembly 26. At this time he must make sure that the marginal portion abuts the edge of the plate 134 and is folded over the projecting edgeof the plate 136. This will cause a diminutive S fold preceding the later blindstitch hem fold which will beformed by the folder assembly 26, the blindstitch hem-also having a generally S shape.

The operator now actuates the manual switch 312, energizing the solenoid of the solenoid controlled valve 240 shutting off air to the cylinders 92,100 and 120, as well as air to the port203 of the cylinder 200. At this time, the pressure at port 202 of cylinder 200 will effect the retraction of the piston rod 198 with the result that the stretch roller 204 moves downwardly, stretching the workpiece over the support cylinders 180,181.

At this time it is pointed out that an important purpose of the stretch roller is to equalize the running time for individual workpieces notwithstanding variations in different workpieces of single size. By stretching the workpieces to a near equal circumference, the effective length of all workpieces will be the same although some workpieces will, of course, be stretched more than others. Also, tensioning of the workpieces helps to prevent any gathering or bunching up as the material passes around the roller.

After the air pressure to the cylinders 92 and 100 has been shut off, the folder sectiond 52,55 of the folder assembly 26 will close. Also, shutting off of air pressure to the cylinder 120 will result in the clamp 125 moving to its material clamping position.

When the stretch roller 204 is moved downwardly by the downward movement of the piston rod 198, the actuator 208 will close the air cylinder 206, pressurizing the cylinder 212 and causing the uncurler blade 218 to be swung inwardly against the outside of the workpiece between the cylindrical member 181 and the stretch roller 204. This will prevent the formation of a curl in the hem area of the workpiece and will eliminate a creasing or folding of such a curl as it passes around the stretch roller 204.

It is to be understood that it is important that the operator keeps the switch 312 closed until operation of the apparatus has been started by closing the switch 257. When the switch 257 is closed, a first circuit from Y the terminal 255 through the coil 258 and the normally closed switch 138 will be completed energizing the coil 258 and shifting the contact 264 into engagement with the contact 263. This will result in the energization of the solenoid controlled valve 241 moving the same to an open position and assuring the interruption of the air supply to the cylinder 92 of the folder assembly 26.

A circuit will also be established from the terminal 255 through the timer 267 to ground through the contact 268.

A holding circuit for the coil 258 will be established through the contacts 264,263 and the lead 266 bypassing the switch 257.

Another circuit between the terminal 255 and the ground for the lead 251 will be established through the contacts 264, 263, the lead 266, coil 258, lead 272, the timer 267 and lead 271, bypassing the normally closed switch 138.

A still further circuit between the terminal 255 and the grounded contact 266 will be completed through the contacts 264,263, the leads 265 and 270, the timer 267 and the lead 271. At this time, it is pointed out that the timer 267 is set so that after a predetermined time period lapse, the circuit through the timer bypassing the switch 138 will open. However, this will have no immediate effect on the operation of the sewing machine, but it causes the remaining circuit through the coil 258 to depend on the switch 138 remaining closed.

When the switch 260 is actuated, although the switch 257 may open, the solenoid of the valve 241 remains energized through the contacts 264,263.

The actuation of the switch 260 through the energization of the coil 258 will cause the contacts 262, 264 to open, thereby disconnecting the timer 283 from the terminal 255, resetting the timer 283. This, in turn, closes a circuit from the terminal 255 through the timer 283 and coil 281 to ground, energizing the coil 281 and resetting the switch 273.

When the switch 273 is reset, a circuit between a further hot terminal 314 to which the movable contact 276 is connected by a lead315, will be established through the contacts 280,278, diode 303, potentiometer 300 and the grounder capacitor 301. As soon as the capacitor 301 is charged, that is with a slight delay, the circuit will be completed through the coil 296 energizing the same and actuating the switch 288.

The solenoid of the valve 244 will be energized through the contacts 276,275 with the result that the normally open valve 244 will be closed, further assuring the shut off of air flow to the cylinders and and to the port 203 of the cylinder 200, this air flow having already been interrupted by the opening of the valve 240. At this time, the operator may release the switch 312 and permit the valve 240 to open.

Contacts 274,276 will open, causing de-energization of lead 304 and the contact 295. The delay in the energization of the coil 296 which brings contact 295 into engagement with contact 294 prevents any possibility of the energization of the solenoid of the valve 225 at this time.

The actuation of the switch 288 will also cause the engagement of the contacts 291,292 with the result that the solenoids of the valves 232 and 235 will be energized shutting off air flow to the cylinder 176 which permits the presser foot to be lowered. When the solenoid of valve 235 is energized, this valve will close, directing air flow to the cylinder 172 and effecting operation of the transmitter clutch, starting the sewing machine 20.

Once the machine has been started, the operator is free to attend to other business, including running a second machine. Upon completion of the stitching cycle, the machine will automatically stop. During the automatic hemming operation, the marginal portion of the workpiece will glide under the clamp 125 and against and over the plates 134,136 of the prefolder 133 with the material being slightly indented thereby preparing a S blindstitch fold. This fold will be completed by the folder assembly 26. As the edge of the workpiece passes out of the folder assembly 26, it will be trimmed by conventional knife means (not shown) generally in alignment with the needle 24. In this manner, the over edge sewing machine 20 may operate automatically to perform the necessary hem stitching operation and the resultant hem is a finished hem.

It is to be understood that the edge of the workpiece continuously passes under the finger 150 of the lever 144 and that any bulge in the material will cause the pivoting of the lever 144 and the opening of the normally closed switch 138. Thus, if the material being hemmed is provided with a side seam, this side seam will engage the finger 150 and pivot the lever 144 so as to momentarily open the switch 138. If it were not for the completion of a bypass circuit through the timer 267, this would result in the machine shutdown. Therefore, it is necessary that the timer 267 be set so that any seam or other bulge forming portion of the edge of the workpiece which may exist will pass the finger 150 prior to the timing out of the timer 267.

[n the normal operation of the apparatus, in the hemming of a tubular workpiece, the hemmed portion will follow the unhemmed portion. When the hemmed portion reaches the clamp 125, it. will pass over the plate portion 131 and in its further advancement engage the sensing finger 150 and effect pivoting of the lever 144 and the opening of the switch 138. Since the timer 267 has already timed out, the circuit through the coil 258 will open. This results in the movement of the contact 264 of switch 260 out of engagement with the contact 263 and back into engagement with the contact 262.

The opening of the contacts 263,264 will result in the opening of the circuit between the terminal 255 and the grounded contact 268, thereby resetting the timer 267. It will also result in the de-energization of the solenoid of the valve 241, permitting the valve 241 to again close with the resultant pressurization of the cylinder 92 and the movement of the folder section 55 to its retracte-d position. This will prevent jamming of the already hemmed portion of the workpiece while the folder section 52 is still in operative position.

It is also to be understood that the circuit through the coil 258 through the lead 266 is now open and the coil 258 will not be energized even when the switch 138 again automatically closes.

The return of the contact 264 into engagement with the contact 262 will re-establish the circuit through the timer'283 between, the terminal 255 and the grounded lead 284 with the result that this will start the timing cycle of the timer 283. The timing cycle of timer 283 determines how long the circuit through the coil 281 will remain closed after the coil 258 is de-energized. When the timer 283 times out, the circuit through contacts 276,275 will open de-energizing the solenoid of valve 244 and permitting the valve 244 to return to its normally closed position. This will result in the cylinder 100 again being pressurized so as to retract the folder section 52 to its open position. The cylinder 120 will also be pressurized with the result that the clamp 125 will be swung to its open position. The opening of the valve 244 will also result in the supplying of pressurized air to the port 203 of the cylinder 200 causing the stretch roller 204 to be shifted upwardly to release the-workpiece. The upward movement of the piston rod 198 of the cylinder 200 will result in the upward movement of the valve actuator 208, permitting the normally closed valve to again close. This will deactlvate the cylinder 212 and cause the uncurler blade 218 to be swung to its inoperative position.

Movement of the contact 280 out of engagement with the contact 278 will cause the collapse of the circuit through the diode 303 and the potentiometer 300. However, the discharge of the capacitor 301 through the coil 296 will delay de-energization of the coil 296 and the movement of the contacts of the switch 288 to their normal positions.

Closing of the contacts 276,274 will result in the momentary energization of the solenoid of the valve 225 (as long as the contacts 295,294 remained engaged) opening the valve 225 and causing the cylinder 157 to be pressurized to actuate the ejector 154. The ejector finger 162 will push the workpiece out of the folder assembly 26 and cause the seam to run off the margin of the material at a slant.

The opening of the valve 225 will also' result in the supplying of air through the air jet 227 to permit the conventional chain cutter of the sewing machine 20 to operate. it is to be understood at this time that the sewing machine 20 is still running.

The capacitor 301, having discharged its energy through the coil 296, the coil 296 will be de-energized with the result that'the contacts 292,295 of the switch 288 will return to their normal positions. The opening of the circuit through the contacts 294,295 will cause the valve 225 to close and the ejector cylinder 157 and the air jet 227 to be deactivated. At the same time, the opening of the contacts 291,292 will result in the deenergization of the solenoids of the valves 232 and 235 with the result that the valve 235 will return to its normally closed position de-activating the cylinder 172 for the transmitter clutch. This will bring about the stopping of the sewing machine 20. On the other hand, the valve 232 will return to its normally open position with the result that the cylinder 176 will be pressurized and the presser foot 25 will be lifted.

The automatic hemming apparatus has now cycled out, and the operator can remove the hemmed workpiece and place a new workpiece in the machine to repeat the hemming operation.

Reference is now made to FIGS. 18 through 22 wherein there is illustrated a mechanism which will replace the clamp and the elements associated therewith. With reference to FIG. 18, a mounting block 315 is provided and is adapted to be secured to the mounting plate 112 by means of screws 316. A pivot plate 317 is pivotally mounted on the left end of the mounting block 315 by means of a pivot pin 318. Pivoting and positioning of the plate 317 is controlled by a cylinder 320.

The right end of the cylinder 320 is pivotally mounted by means of a pin 321 to a pair of brackets 322 which, in turn, are secured to the right end of the block 315. The cylinder 320 includes a piston rod 323 which has adjustably mounted thereon a bifurcated fitting 324 which is, in turn, pivotally connected by means of a pivot pin 325 to an upstanding block portion 326 of the pivot plate 317. The cylinder 320 is a single acting cylinder with the piston rod 323 normally extended. In this position, the pivot plate 317 is normally urged towards the mounting plate 112 and is pivoted away from the mounting plate 112 when the cylinder 320 is pressurized.

At the left end of the pivot plate 317 there is secured by means of screws 327 a prefolder and guide plate 328. The plate 328 is spaced below the plate 317 by means of a spacer 330 through which the screws 327 pass. It is also to be noted that the plate 328 has a beveled edge 331 to allow easier prefolding of the material to be hemmed. The spacer 330 allows the prefolder and guide plate 328 to drop low enough, when it is in its operating position, to put a very slight drag on the material in order to keep the material in line with the prefolder plate 136 and the folder assembly 26.

The pivot plate 317 has a bottom edge 332 and intermediate the ends of the edge 332 the plate 317 is provided with a guide slot 333. A further guiding element is provided by securing a long square-shaped block 334 to the edge 332 by screws 335 on opposite sides of the slot 333. The slot 333 and the block 334 serve to guide a slide block 336 for sliding movement, as is best shown in FIG. 21. The block 336 has secured on its lower surface an uncurler plate 337. The block 336 and the uncurler plate 337 are slid back and forth in the guide slot 333 and in timed relation with the pivoting of the pivot plate 317 by a link 338. The link 338 is pivotally connected by a shoulder screw 340 to the block 336 at one of its ends. At the other end, the link 338 is pivotally connected by a pin 341 to a fitting 342 which is carried by the piston rod of an air cylinder 343. The air cylinder 343 is mounted on the block 315 by means of a bracket 344 which is secured to the lower edge of the block 315 by means of screws 345.

A flat rectangular guide plate 346 is secured by screws 347 to the upper edge 348 of the pivot plate 317. The guide plate 346 serves to keep the sewn hem to the left at it comes around so that the sewn hem will be assured of engaging the finger 150 and pivoting the lever 144 so as to open the normally closed switch 138. The plate 346 primarily functions as an uncurler during the last third of the sewing cycle at which time the edge of the workpieces has moved to the left out from under the uncurler plate 337 and the plate 346 takes over for the plate 337.

Referring now to the partially illustrated control system of FIG. 22, it will be seen that in lieu of the line 243, after passing through the one way flow control valve 245 being connected to the cylinder 120 for the clamp 125, as illustrated in FIG. 17, the line 243 passes through a second one-way control valve 350 and an adjustable flow control valve 351, is connected to the cylinder 343 for the uncurler 337. In addition, a line 352 is connected to the line 243 between the valves 350 and 351 and leads to the cylinder 320 for the combined prefolder and guide 328.

The timing between the operation of the prefolder 328 and the uncurler plate 337 is such that, at the beginning of the sewing cycle, the uncurler plate 337 will not be moved to the right until the prefolder plate 328 has been moved into slight contact with the material. This arrangement assures contact of the prefolder plate with the material and at the same time permits the uncurler plate to accomplish a smoothing action. It is also to be understood that at the end of the sewing cycle, the uncurler plate 337 will be pushed to the left before the prefolder plate 328 is lifted.

It is further to be noted that the edge 331 of the prefolder plate 328 is disposed at a slight angle to the direction of material movement. This angle, when properly adjusted, will control the proper folding of the material at the prefolder 133 and will also, as indicated above, initiate a prefolding operation. It is possible under certain circumstances that the prefolding operation of the prefolder plate 328 would be sufficient to eliminate the prefolder 133. The prefolder plate 328, along with the prefolder 133 accurately guides the fold to the hem folder 26.

Although only preferred embodiments of the automatic hemming apparatus have been specifically illustrated and described herein, it is to be understood that minor variations may be made in the hemming apparatus and the controls therefor without departing from the spirit and scope of the invention, as defined by the appended claims.

We claim:

1. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an intergral blindstitch hem on a tubular workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a tubular workpiece into an S- shaped fold and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said material guide being in the form of a clamp cooperating with a material engaging and supporting plate, said hem folding mechanism including relatively movable hem folding members and actuator means therefor, and said clamp has separate actuator means, and control means for effecting the operation in unison of both said actuator means to selectively fold and release material.

2. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said material guide means being in the form of a combined prefolder and guide plate cooperating with a material engaging and supporting plate, and actuator means for selectively positioning said combined prefolder and guide plate relative to said material engaging and supporting plate to apply a light drag on material to effect the guiding of material.

3. The automatic hemming apparatus of claim 2 wherein said combined prefolder and guide plate has a beveled edge disposed in acute angular relation to the normal path of material thereover.

4. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said material guide means being in the form of a combined prefolder and guide plate cooperating with a material engaging and supporting plate, and an uncurler disposed in advance of said combined prefolder and guide plate.

5. The automatic hemming apparatus of claim 4 together with a second uncurler disposed downstream of said first mentioned uncurler and generally in cooperative relation with said combined prefolder and guide plate.

6. The automatic hemming apparatus of claim 5 wherein said combined prefolder and guide plate and said first and second uncurlers are all mounted on a support plate mounted separate and apart from said material engaging and supporting plate and being positioned by said support plate.

7. The automatic hemming apparatus of claim 6 wherein said support plate is in the form of a pivot plate mounted for pivotal movement, and means for selectively positioning said pivot plate.

8. The automatic hemming apparatus of claim 5 wherein said second uncurler is fixedly positioned relative to said combined prefolder and guide plate, and said first mentioned uncurler has means movably mounting the same relative to said combined prefolder and guide plate.

9. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, a sewn hem detector positioned in the path of material advancing towards said needle, a material ejector disposed adjacent the path of material moving towards said needle for moving material being hemmed laterally away from said needle to terminate a hem stitching operation, and control means actuated by said detector for actuating said material ejector.

10. The automatic hemming apparatus of claim 9 together with thread chain cutter means mounted on said sewing machine downstream of said needle in the direction of material movement, and said control means being operative for actuating said thread chain cutter means simultaneously with the actuation of said material ejector.

ll. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, a sewn hem detector positioned in the path of material advancing towards said needle, a material ejector disposed adjacent the path of material moving towards said needle for moving material being hemmed laterally away from said needle to terminate a hem stitching operation, said hem folding mechanism includes relatively movable hem folding members and actuator means therefor, and control means actuated by said detector for actuating said material ejector and effecting operation of said actuator means to move said hem folding members to a material releasing position.

12. The automatic hemming apparatus of claim 11 wherein said control means are parts of a control system including a by-pass control rendering said control means ineffective, and timer means in said by-pass control for rendering said detector inoperative whereby operation of said detector by seams and like projections will not prematurely actuate said control means.

13. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said apparatus being particularly adapted for hemming tubular material and including a rotary support cooperable with said cloth plate to support tubular material being hemmed, and a stretch roller remote from said cloth plate and said rotary support, said stretch roller cooperating with said rotary support for maintaining tubular material in a hemable position.

14. The automatic hemming apparatus of claim 13 wherein said stretch roller has adjustable mounting means for adjusting the operative position of said stretch roller in accordance with the dimension of the tubular material being hemmed.

15. The automatic hemming apparatus of claim 13 wherein said stretch roller has mounting means for moving said stretch roller to a predetermined position relative to said rotary support wherein all tubular material of the same relative size is stretched to a substantially uniform circumference.

16. The automatic hemming apparatus of claim 15 wherein an uncurler is disposed along the path of material movement between said rotary support and said stretch roller for eliminating curls in material before the material passes around said stretch roller.

17. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said hem folding mechanism including relatively movable folder sections, control means for controlling the operation of said sewing machine, control means connected to said folder sections for opening and closing said hem folding mechanism, and ejector means disposed adjacent the path of material moving towards said needle for moving a material edge portion out of alignment with said nee dle, detector means positioned in the path of material advancing towards said needle for sensing the end of the material to be stitched; and an automatic control system connected to all of said control means and said ejector means for sequentially moving the edge of ma- I wherein said hem folding mechanism includes two separately positionable folder sections, and said control system includes means for moving said folder sections to open positions in timed sequence.

20. The automatic hemming apparatus of claim 18 wherein said hem folding mechanism includes two separately positionable folder sections, and said automatic control system including means for first moving one of said folder sections to an open position, means for next moving the other of said folder sections to an open position, then actuating said ejector means to lead material away from said needle, and then discontinue the operation of said sewing machine.

21. The automatic hemming apparatus of claim 20 wherein said guide means includes a control device operable after the movement of said one folder section to an open position to release material being hemmed.

22. The automatic hemming apparatus of claim 20 wherein said time delay means includes a pair of sequentially operable timers.

23. The automatic hemming apparatus of claim 20 wherein said time delay means includes a pair of sequentially operable timers, and one timing circuit.

24. The automatic hemming apparatus of claim 20 wherein said time delay means includes a pair of sequentially operable timers, and three sequentially operable delay devices. 

1. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an intergral blindstitch hem on a tubular workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a tubular workpiece into an Sshaped fold and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said material guide being in the form of a clamp cooperating with a material engaging and supporting plate, said hem folding mechanism including relatively movable hem folding members and actuator means therefor, and said clamp has separate actuator means, and control means for effecting the operation in unison of both said actuator means to selectively fold and release material.
 2. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said material guide means being in the form of a combined prefolder and guide plate cooperating with a material engaging and supporting plate, and actuator means for selectively positioning said combined prefolder and guide plate relative to said material engaging and supporting plate to apply a light drag on material to effect the guiding of material.
 3. The automatic hemming apparatus of claim 2 wherein said combined prefolder and guide plate has a beveled edge disposed in acute angular relation to the normal path of material thereover.
 4. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integraL hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said material guide means being in the form of a combined prefolder and guide plate cooperating with a material engaging and supporting plate, and an uncurler disposed in advance of said combined prefolder and guide plate.
 5. The automatic hemming apparatus of claim 4 together with a second uncurler disposed downstream of said first mentioned uncurler and generally in cooperative relation with said combined prefolder and guide plate.
 6. The automatic hemming apparatus of claim 5 wherein said combined prefolder and guide plate and said first and second uncurlers are all mounted on a support plate mounted separate and apart from said material engaging and supporting plate and being positioned by said support plate.
 7. The automatic hemming apparatus of claim 6 wherein said support plate is in the form of a pivot plate mounted for pivotal movement, and means for selectively positioning said pivot plate.
 8. The automatic hemming apparatus of claim 5 wherein said second uncurler is fixedly positioned relative to said combined prefolder and guide plate, and said first mentioned uncurler has means movably mounting the same relative to said combined prefolder and guide plate.
 9. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, a sewn hem detector positioned in the path of material advancing towards said needle, a material ejector disposed adjacent the path of material moving towards said needle for moving material being hemmed laterally away from said needle to terminate a hem stitching operation, and control means actuated by said detector for actuating said material ejector.
 10. The automatic hemming apparatus of claim 9 together with thread chain cutter means mounted on said sewing machine downstream of said needle in the direction of material movement, and said control means being operative for actuating said thread chain cutter means simultaneously with the actuation of said material ejector.
 11. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, a sewn hem detector positioned in the path of material advancing towards said needle, a material ejector disposed adjacent the path of material moving towards said needle for moving material being hemmed laterally away from said needle to terminate a hem stitching operaTion, said hem folding mechanism includes relatively movable hem folding members and actuator means therefor, and control means actuated by said detector for actuating said material ejector and effecting operation of said actuator means to move said hem folding members to a material releasing position.
 12. The automatic hemming apparatus of claim 11 wherein said control means are parts of a control system including a by-pass control rendering said control means ineffective, and timer means in said by-pass control for rendering said detector inoperative whereby operation of said detector by seams and like projections will not prematurely actuate said control means.
 13. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said apparatus being particularly adapted for hemming tubular material and including a rotary support cooperable with said cloth plate to support tubular material being hemmed, and a stretch roller remote from said cloth plate and said rotary support, said stretch roller cooperating with said rotary support for maintaining tubular material in a hemable position.
 14. The automatic hemming apparatus of claim 13 wherein said stretch roller has adjustable mounting means for adjusting the operative position of said stretch roller in accordance with the dimension of the tubular material being hemmed.
 15. The automatic hemming apparatus of claim 13 wherein said stretch roller has mounting means for moving said stretch roller to a predetermined position relative to said rotary support wherein all tubular material of the same relative size is stretched to a substantially uniform circumference.
 16. The automatic hemming apparatus of claim 15 wherein an uncurler is disposed along the path of material movement between said rotary support and said stretch roller for eliminating curls in material before the material passes around said stretch roller.
 17. An automatic hemming apparatus comprising a sewing machine having hem forming means thereon for forming an integral hem on a workpiece, said hem forming means including a needle and a cloth plate, a hem folding mechanism for folding an edge portion only of a workpiece and disposed in cooperating overlying relation to said cloth plate in advance of said needle and generally in alignment therewith, a prefolder for receiving a workpiece on which an integral hem is to be formed disposed in advance of said hem folding mechanism, and material guide means for cooperating with said prefolder to guide material into cooperating relationship with said prefolder, said hem folding mechanism including relatively movable folder sections, control means for controlling the operation of said sewing machine, control means connected to said folder sections for opening and closing said hem folding mechanism, and ejector means disposed adjacent the path of material moving towards said needle for moving a material edge portion out of alignment with said needle, detector means positioned in the path of material advancing towards said needle for sensing the end of the material to be stitched; and an automatic control system connected to all of said control means and said ejector means for sequentially moving the edge of material being hemmed away from said needle and for discontinuing the operation of said sewing machine.
 18. The automatic hemming apparatus of claim 17 wherein said automatic control system includes adjustablE time delay means for accurately timing the actuation of said ejector means and said control means.
 19. The automatic hemming apparatus of claim 18 wherein said hem folding mechanism includes two separately positionable folder sections, and said control system includes means for moving said folder sections to open positions in timed sequence.
 20. The automatic hemming apparatus of claim 18 wherein said hem folding mechanism includes two separately positionable folder sections, and said automatic control system including means for first moving one of said folder sections to an open position, means for next moving the other of said folder sections to an open position, then actuating said ejector means to lead material away from said needle, and then discontinue the operation of said sewing machine.
 21. The automatic hemming apparatus of claim 20 wherein said guide means includes a control device operable after the movement of said one folder section to an open position to release material being hemmed.
 22. The automatic hemming apparatus of claim 20 wherein said time delay means includes a pair of sequentially operable timers.
 23. The automatic hemming apparatus of claim 20 wherein said time delay means includes a pair of sequentially operable timers, and one timing circuit.
 24. The automatic hemming apparatus of claim 20 wherein said time delay means includes a pair of sequentially operable timers, and three sequentially operable delay devices. 